function! Append()
python3 << EOF
import vim
## 获取当前buffer
cur_buf = vim.current.buffer
## 当前buffer行数
lens = len(cur_buf)

##在文件头部插入n行
def insert_header():
    line_nr = lens
    ##插入4行
    cur_buf.append("")
    cur_buf.append("")
    cur_buf.append("")
    cur_buf.append("")
    lenss = len(cur_buf)
    print(lenss," lines")
    for nr in range(lenss-4):
        cur_buf[lenss-nr-1] = cur_buf[lenss-4-nr-1]
        
insert_header()
print(len(cur_buf))
print(cur_buf[-1])
print(cur_buf[0])
print(cur_buf[2])
EOF
endfunction
